2,351 research outputs found

    A novel locus (CORD12) for autosomal dominant cone-rod dystrophy on chromosome 2q24.2-2q33.1

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    <p>Abstract</p> <p>Background</p> <p>Rod-cone dystrophy, also known as retinitis pigmentosa (RP), and cone-rod dystrophy (CRD) are degenerative retinal dystrophies leading to blindness. To identify new genes responsible for these diseases, we have studied one large non consanguineous French family with autosomal dominant (ad) CRD.</p> <p>Methods</p> <p>Family members underwent detailed ophthalmological examination. Linkage analysis using microsatellite markers and a whole-genome SNP analysis with the use of Affymetrix 250 K SNP chips were performed. Five candidate genes within the candidate region were screened for mutations by direct sequencing.</p> <p>Results</p> <p>We first excluded the involvement of known adRP and adCRD genes in the family by genotyping and linkage analysis. Then, we undertook a whole-genome scan on 22 individuals in the family. The analysis revealed a 41.3-Mb locus on position 2q24.2-2q33.1. This locus was confirmed by linkage analysis with specific markers of this region. The maximum LOD score was 2.86 at θ = 0 for this locus. Five candidate genes, <it>CERKL</it>, <it>BBS5, KLHL23, NEUROD1</it>, and <it>SF3B1 </it>within this locus, were not mutated.</p> <p>Conclusion</p> <p>A novel locus for adCRD, named <it>CORD12</it>, has been mapped to chromosome 2q24.2-2q33.1 in a non consanguineous French family.</p

    De novo intrachromosomal gene conversion from OPN1MW to OPN1LW in the male germline results in Blue Cone Monochromacy

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    X-linked cone dysfunction disorders such as Blue Cone Monochromacy and X-linked Cone Dystrophy are characterized by complete loss (of) or reduced L- and M- cone function due to defects in the OPN1LW/OPN1MW gene cluster. Here we investigated 24 affected males from 16 families with either a structurally intact gene cluster or at least one intact single (hybrid) gene but harbouring rare combinations of common SNPs in exon 3 in single or multiple OPN1LW and OPN1MW gene copies. We assessed twelve different OPN1LW/MW exon 3 haplotypes by semi-quantitative minigene splicing assay. Nine haplotypes resulted in aberrant splicing of ≥20% of transcripts including the known pathogenic haplotypes (i.e. ‘LIAVA’, ‘LVAVA’) with absent or minute amounts of correctly spliced transcripts, respectively. De novo formation of the ‘LIAVA’ haplotype derived from an ancestral less deleterious ‘LIAVS’ haplotype was observed in one family with strikingly different phenotypes among affected family members. We could establish intrachromosomal gene conversion in the male germline as underlying mechanism. Gene conversion in the OPN1LW/OPN1MW genes has been postulated, however, we are first to demonstrate a de novo gene conversion within the lineage of a pedigree

    The kinematics of swimming and relocation jumps in copepod nauplii

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    Copepod nauplii move in a world dominated by viscosity. Their swimming-by-jumping propulsion mode, with alternating power and recovery strokes of three pairs of cephalic appendages, is fundamentally different from the way other microplankters move. Protozoans move using cilia or flagella, and copepodites are equipped with highly specialized swimming legs. In some species the nauplius may also propel itself more slowly through the water by beating and rotating the appendages in a different, more complex pattern. We use high-speed video to describe jumping and swimming in nauplii of three species of pelagic copepods: Temora longicornis, Oithona davisae and Acartia tonsa. The kinematics of jumping is similar between the three species. Jumps result in a very erratic translation with no phase of passive coasting and the nauplii move backwards during recovery strokes. This is due to poorly synchronized recovery strokes and a low beat frequency relative to the coasting time scale. For the same reason, the propulsion efficiency of the nauplii is low. Given the universality of the nauplius body plan, it is surprising that they seem to be inefficient when jumping, which is different from the very efficient larger copepodites. A slow-swimming mode is only displayed by T. longicornis. In this mode, beating of the appendages results in the creation of a strong feeding current that is about 10 times faster than the average translation speed of the nauplius. The nauplius is thus essentially hovering when feeding, which results in a higher feeding efficiency than that of a nauplius cruising through the water

    Genetic regulation of pituitary gland development in human and mouse

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    Normal hypothalamopituitary development is closely related to that of the forebrain and is dependent upon a complex genetic cascade of transcription factors and signaling molecules that may be either intrinsic or extrinsic to the developing Rathke’s pouch. These factors dictate organ commitment, cell differentiation, and cell proliferation within the anterior pituitary. Abnormalities in these processes are associated with congenital hypopituitarism, a spectrum of disorders that includes syndromic disorders such as septo-optic dysplasia, combined pituitary hormone deficiencies, and isolated hormone deficiencies, of which the commonest is GH deficiency. The highly variable clinical phenotypes can now in part be explained due to research performed over the last 20 yr, based mainly on naturally occurring and transgenic animal models. Mutations in genes encoding both signaling molecules and transcription factors have been implicated in the etiology of hypopituitarism, with or without other syndromic features, in mice and humans. To date, mutations in known genes account for a small proportion of cases of hypopituitarism in humans. However, these mutations have led to a greater understanding of the genetic interactions that lead to normal pituitary development. This review attempts to describe the complexity of pituitary development in the rodent, with particular emphasis on those factors that, when mutated, are associated with hypopituitarism in humans

    Performance and Operation of the CMS Electromagnetic Calorimeter

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    The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

    Study of vector mesons in dimuon production in a large kinematic region in p-W and S-W interactions at 200 GeV/c/nucleon

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    Results are presented on ρ+ω\rho+\omega, ϕ\phi and J/ΨJ/\Psi production in p--W and 32^{32}S--W interactions at 200~GeV/c/nucleon measured via the dimuon decay in a large kinematic region. The data are normalized to the charged particle multiplicity in the same rapidity interval. They have been %CORR 1 obtained collected using the HELIOS/3 muon spectrometer at the CERN SPS. %CORR 2 and The ratio ϕ/(ρ+ω)\phi/{(\rho+\omega)} increases between proton and sulphur projectiles, and is further enhanced going from peripheral to central nucleus-nucleus interactions. This results from an increase in the number of produced ϕ\phi's per charged particle. The increase in the ratio ϕ/(ρ+ω)\phi/{(\rho+\omega)} is not clearly dependent on pT_T, but appears larger at higher rapidities, due to kinematic effects %CORR 3 and in conjunction with varying acceptance. J/ΨJ/\Psi production, likewise normalized to charged multiplicity, is significantly lower in S--W compared to p--W interactions

    Decreased availability of antimalarials in the private sector following the policy change from chloroquine to sulphadoxine-pyrimethamine in the Kilombero Valley, Tanzania

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    BACKGROUND: Malaria control strategies emphasize the need for prompt and effective treatment of malaria episodes. To increase treatment efficacy, Tanzania changed its first-line treatment from chloroquine to sulphadoxine-pyrimethamine (SP) in 2001. The effect of this policy change on the availability of antimalarials was studied in rural south-eastern Tanzania. METHODS: In 2001 and 2004, the study area was searched for commercial outlets selling drugs and their stocks were recorded. Household information was obtained from the local Demographic Surveillance System. RESULTS: From 2001 to 2004, the number of general shops stocking drugs increased by 15% and the number of drug stores nearly doubled. However, the proportion of general shops stocking antimalarials dropped markedly, resulting in an almost 50% decrease of antimalarial selling outlets. This led to more households being located farther from a treatment source. In 2004, five out of 25 studied villages with a total population of 13,506 (18%) had neither a health facility, nor a shop as source of malaria treatment. CONCLUSION: While the change to SP resulted in a higher treatment efficacy, it also led to a decreased antimalarial availability in the study area. Although there was no apparent impact on overall antimalarial use, the decline in access may have disproportionately affected the poorest and most remote groups. In view of the imminent policy change to artemisinin-based combination therapy these issues need to be addressed urgently if the benefits of this new class of antimalarials are to be extended to the whole population

    Mutation Detection in Patients with Retinal Dystrophies Using Targeted Next Generation Sequencing

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    Retinal dystrophies (RD) constitute a group of blinding diseases that are characterized by clinical variability and pronounced genetic heterogeneity. The different nonsyndromic and syndromic forms of RD can be attributed to mutations in more than 200 genes. Consequently, next generation sequencing (NGS) technologies are among the most promising approaches to identify mutations in RD. We screened a large cohort of patients comprising 89 independent cases and families with various subforms of RD applying different NGS platforms. While mutation screening in 50 cases was performed using a RD gene capture panel, 47 cases were analyzed using whole exome sequencing. One family was analyzed using whole genome sequencing. A detection rate of 61% was achieved including mutations in 34 known and two novel RD genes. A total of 69 distinct mutations were identified, including 39 novel mutations. Notably, genetic findings in several families were not consistent with the initial clinical diagnosis. Clinical reassessment resulted in refinement of the clinical diagnosis in some of these families and confirmed the broad clinical spectrum associated with mutations in RD genes
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